将 function 作为参数传递给另一个 function

Question

def pivot2(arr,start=0,end=len(arr)):
    pivot=arr[start]
    swapid=start
    for x in range(start+1,end):
        if(pivot>arr[x]):
            swapid +=1
            swap(arr,swapid,x)
            print(arr)
    swap(arr,start,swapid)
    return swapid

def swap(arr,i,j):
    temp=arr[i]
    arr[i]=arr[j]
    arr[j]=temp

In pivot2 function I get an error that arr name not defined and when I remove end=len(arr) from the arguments the function works, why can't I pass len(arr) as an argument in Python?

Answer 1

因为您将 arr 作为参数传递并且它不是变量 python 将尝试找到引发该错误的变量

要解决此问题，而不是将 len(arr) 放入参数中，请将其放入实际的 function

def pivot2(arr,start=0):
    end=len(arr)
    pivot=arr[start]
    swapid=start
    for x in range(start+1,end):
        if(pivot>arr[x]):
            swapid +=1
            swap(arr,swapid,x)
            print(arr)
    swap(arr,start,swapid)
    return swapid